30-003 Kraków, Poland - Engineering / Ingeniør

About the position
The BESS Lead Engineer is responsible for the full engineering lifecycle of BESS projects — from technical design and system integration through to commissioning, optimisation and ongoing performance management. The role requires strong hands-on experience with large-scale battery storage systems. The BESS Lead Engineer will be responsible for building the BESS competences within the organization and systems necessary to support our clients in the full lifecycle of BESS projects. This position reports to the Chief Operating Officer.

The BESS Lead Engineer shall work closely with project developers, EPC contractors, grid operators and OEM technology partners to deliver safe, reliable and high-performance BESS installations for utility-scale, industrial and behind-the-meter applications.

Key Responsibilities
System Design & Engineering

Understand customer technical and functional requirements
Lead BESS system design including single-line diagrams, protection coordination, DC and AC architecture layout and thermal management systems
Define technical specifications for battery modules, PCS (Power Conversion Systems), BMS (Battery Management Systems), EMS (Energy Management Systems) and auxiliary equipment
Conduct grid connection studies — fault level analysis, harmonics, power quality and load flow — in coordination with DNOs and TSOs
Review technical documentation: design basis, equipment datasheets, interface control documents, FAT/SAT protocols
Evaluate and compare BESS OEM technologies (CATL, BYD, Saft, Samsung SDI, Fluence, Tesla Megapack etc.) for project suitability

Project Execution & Commissioning

Manage technical aspects of BESS project execution from initial studies through to commissioning and handover
Coordinate with EPC contractors, civil and electrical subcontractors, and OEM service teams during construction and commissioning phases
Witness Factory Acceptance Tests (FAT), Site Acceptance Tests (SAT) for all included sub-systems
Develop and execute overall site tests
Witness BESS performance testing: capacity test, round-trip efficiency, response time, ramp rate and auxiliary energy consumption

Grid Integration & Compliance

Ensure BESS design and operation comply with applicable grid codes (ENTSO-E, national TSO/DNO requirements)
Support grid services capability design: Frequency Containment Reserve (FCR), automatic Frequency Restoration Reserve (aFRR), peak shaving, load shifting and black start
Liaise with grid operators and permitting authorities on connection agreements, protection settings and operational requirements
Support preparation of grid code compliance submissions, type approval documentation and technical assessments

Performance Monitoring & Optimisation

Analyse BESS operational data — State of Charge (SoC), State of Health (SoH), temperature, cycling, round-trip efficiency — and report on performance vs contractual guarantees
Develop and implement performance improvement strategies including dispatch optimisation, thermal management and degradation management
Define and monitor Key Performance Indicators (KPIs) for BESS availability, round-trip efficiency, capacity retention and response accuracy
Support revenue optimisation through EMS dispatch strategy design for energy arbitrage, ancillary services and capacity markets

Safety, HSE & Standards Compliance

Lead BESS safety engineering including risk assessment (HAZID, FMEA), arc flash analysis, thermal runaway mitigation and fire suppression system design
Ensure compliance with IEC 62933, IEC 61851, IEC 62619, UN 38.3, NFPA 855 and applicable national standards
Conduct and review site HSE assessments and safe work method statements for BESS installation and commissioning activities
Maintain awareness of emerging BESS safety standards and regulatory developments in target markets

Technical Support & Business Development

Provide technical due diligence support for BESS project acquisitions, technology selection and OEM contract negotiations
Prepare technical sections of tender documents, RfPs and proposals
Mentor colleagues and share technical knowledge across the organisation

Required Qualifications

Bachelor or Masters degree in Electrical Engineering.
Strong analytical and problem-solving skills — able to diagnose complex system-level issues under time pressure
Excellent written and verbal communication — able to produce clear technical reports for engineering, commercial and non-technical audiences
Structured and methodical approach to commissioning and testing and high attention to detail
Self-driven and able to work independently on multi-site projects with minimal day-to-day supervision
Strong interpersonal skills, and in this respect to work effectively with OEMs, contractors, grid operators and clients across multiple cultures
Commercial awareness: understands project economics, contract structures and the business impact of engineering decisions
Commitment to safety — applies rigorous HSE standards without exception
Passion for the energy transition and genuine interest in advancing battery storage technology
Proficiency in English at a negotiation level is required; proficiency in a third language is an advantage.

Practical Information

Travel: Expect up to 100 days of travel per year.
Location: Krakow, Poland.
Work Culture: Collaborative environment where your input directly affects workflow efficiency.

How to apply
If you have any questions or would like to know more about the position, please contact CEO AET Poland Szczepan Wójcik at + 48 51 97 03 35 7 or COO Klaus Munck Rasmussen at + 45 50 77 76 66.

We look forward to receiving your application!

About the company
AET is a leading engineering and construction company that supplies power plants, cogeneration plants and boiler plants in the size range 25 - 170 MWt. Our business includes planning, procurement, management, construction and servicing of sustainable energy plants.

We have existed for more than 25 years and have our headquarters in Aalborg as well as a smaller office in Krakow/Poland.

Battery Energy Storage Systems (BESS) Lead Engineer